column store: All content tagged as column store in NoSQL databases and polyglot persistence
- We say we can do failover in a couple of seconds. We want to make it subsecond, but we can’t do that reliably yet. In HBase this story is much more mixed.
- We wanted to really reduce complexity, as a result, you can just apt-get install c5 on each node and you are done. It’s one daemon, one log file, and that’s it. No xmx nonsense, and almost no tuning or config files. I don’t know if you have dealt with hadoop before, but the complexity is high.
- Finally we have a much more advanced wireformat. In fact it’s advanced by being simple (protobufs + http). As a result clients in languages other than java become very easy, without a thrift client.
Are we in a new stage of NoSQL databases: “X that doesn’t suck”?
Original title and link: OhmData C5: an improved HBase ( ©myNoSQL)
After re-reading HyperDex’s comparison of Cassandra, MongoDB, and Riak backups, I’ve realized there are no links to the corresponding docs. So here they are:
Cassandra backs up data by taking a snapshot of all on- disk data files (SSTable files) stored in the data directory.
You can take a snapshot of all keyspaces, a single keyspace, or a single table while the system is online. Using a parallel ssh tool (such as pssh), you can snapshot an entire cluster. This provides an eventually consistent backup. Although no one node is guaranteed to be consistent with its replica nodes at the time a snapshot is taken, a restored snapshot resumes consistency using Cassandra’s built-in consistency mechanisms.
After a system-wide snapshot is performed, you can enable incremental backups on each node to backup data that has changed since the last snapshot: each time an SSTable is flushed, a hard link is copied into a /backups subdirectory of the data directory (provided JNA is enabled).
Basically three are three ways to backup MongoDB:
- Using MMS
- Copying underlying files
Riak’s backup operations are pretty different for the two main storage backends, Bitcask and LevelDB, used by Riak:
Choosing your Riak backup strategy will largely depend on the backend configuration of your nodes. In many cases, Riak will conform to your already established backup methodologies. When backing up a node, it is important to backup both the ring and data directories that pertain to your configured backend.
Note: I’d be happy to update this entry with links to docs on what tools and solutions other NoSQL databases (HBase, Redis, Neo4j, CouchDB, Couchbase, RethinkDB) are providing.
✚ Considering that creating backups is as useful as making sure that these will actually work when trying to restore, I’m wondering why there are no tools that can validate a backup without forcing a complete restore. The two mechanisms are not equivalent, but for large size databases this might simplify a bit the process and increase the confidence of the users.
Original title and link: Quick links for how to backup different NoSQL databases ( ©myNoSQL)